title: Induction of apoptosis by metformin in epithelial ovarian cancer: involvement of the Bcl-2 family proteins.
abstract: OBJECTIVE
  The aims of the study were to evaluate the ability of metformin to induce apoptosis in epithelial ovarian cancer cell lines and to identify the pathways involved in this effect.
  
  
  METHODS
  After treatment with metformin and/or cisplatin, OVCAR-3 and OVCAR-4 cellular apoptosis was assessed by flow cytometry and caspase 3/7 activity. Cell cycle analysis was also performed by flow cytometry as well. Modulation of protein expression of the Bcl-2 family after treatment with metformin and/or cisplatin was determined by Western blotting.
  
  
  RESULTS
  Metformin induced apoptosis in OVCAR-3 and OVCAR-4 cell lines in an AMPK-independent manner and provoked a cell cycle arrest in the S and G2/M phase. Moreover, we established that metformin can induce apoptosis in OVCAR-3 and OVCAR-4 cells by activating caspases 3/7, down-regulating Bcl-2 and Bcl-xL expression, and up-regulating Bax and Bad expression. The induction of apoptosis by metformin was also enhanced by cisplatin and combination of these drugs did not modulate the expression of Bcl-2 family proteins in OVCAR-3 cell line, whereas the effect was enhanced in OVCAR-4 cell line.
  
  
  CONCLUSIONS
  Bcl-xL and Bcl-2 targeted strategies were suggested to constitute an effective therapeutic tool for the treatment of chemoresistant ovarian carcinoma, in conjunction with conventional chemotherapy. These data are relevant to ongoing translational research efforts and clinical trials exploring a possible protective effect of metformin against ovarian cancer, including Bcl-2 inhibition.
authors.affiliation: Division of Gynecologic Oncology, Jewish General Hospital, McGill University, 3755 Cote-Ste-Catherine Road, Montreal, Quebec, Canada.
authors.forename: Amber
authors.initials: A
authors.lastname: Yasmeen
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Beauchamp
authors.forename: Ettie
authors.initials: E
authors.lastname: Piura
authors.forename: Eric
authors.initials: E
authors.lastname: Segal
authors.forename: Michael
authors.initials: M
authors.lastname: Pollak
authors.forename: Walter H
authors.initials: WH
authors.lastname: Gotlieb
mesh_terms: D000091162:AMP-Activated Protein Kinase Kinases; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D000077216:Carcinoma, Ovarian Epithelial; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008687:Metformin / Q000008:administration & dosage / Q000494:pharmacology*; D009375:Neoplasms, Glandular and Epithelial / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D011494:Protein Kinases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D008687:Metformin; D011494:Protein Kinases; D000091162:AMP-Activated Protein Kinase Kinases; D002945:Cisplatin